Microfabrication of 32x32 uncooled IR focal plane array

Design and fabrication of a 32x32 uncooled IR focal plane array based on Si micromachining technique is presented. Ferroelectric lead zirconate titanate (PZT) thin film was used as the sensing material in the array. The PZT thin film was deposited on the top of Si substrate coated with silicon dioxide, silicon nitrite, titanium and platinum. Sol-gel method was used to deposit the PZT film. Size of the sensing element is 60x80 mum(2) and pixel size is 80x100 mum(2), yields a filling factor of 60%. Zn order to eliminate the thermal loss from the PZT elements to silicon substrate to improve the response of the IR sensor, silicon substrate under the sensing element was etched off using KOH micromachining technique. Membrane composed of silicon dioxide and silicon nitrite was formed. Membrane size as large as 3.2x3.8 mm(2) is fabricated. Results proved that micromachining is an effective way in fabricating uncooled IR focal plane array based on ferroelectric thin films. The process is totally compatible with standard IC fabrication techniques.